Electronic components tend generate unwanted heat during use which should be channeled away from the device for proper operation. Heat sinks are often employed to radiate heat away from the device. Fans are also often used to more efficiently move heat away from the device to keep it cool and operating at a suitable temperature.
The trend to ultra thin notebooks and high density blade servers may make it more difficult to provide sufficient cooling with conventional airflow cooling, due to the space constraints. Smaller fans may thus be used running at higher speeds to move more air; however, this tends to create more acoustic noise.
Low acoustic noise may be important given end user preferences, eco labels, and emerging governmental procurement directives. The use of acoustic absorbers may allow for an increased airflow at the same noise level, but there is no room in the ultra thin systems for traditional, bulky acoustic absorbers such as foams.
Absorbing materials such as foams may be applied, but they are too bulky and do not fit in ultra thin form factors. In addition, the open cell foams lead to airflow loss in the system. Finally, these materials are relatively expensive and hard to integrate. Therefore, acoustic absorbers are usually not used in most electronic devices. Radial blowers and cross flow blowers are available, but they are not optimized and do not contain an integrated noise control solutions.